Gradually regaining consciousness, I realized this was no dream it had really happened. Maybe I’ll wake up and get out of this mess, I mused. “My next recollection was a hazy thought that I was having a bad dream. From that point, I was just along for the ride. The SR-71 then literally disintegrated around us. Still trying to communicate with Jim, I blacked out, succumbing to extremely high g-forces. I learned later the time from event onset to catastrophic departure from controlled flight was only 2-3 sec. “Everything seemed to unfold in slow motion. “The cumulative effects of system malfunctions, reduced longitudinal stability, increased angle-of-attack in the turn, supersonic speed, high altitude and other factors imposed forces on the airframe that exceeded flight control authority and the Stability Augmentation System’s ability to restore control.
However, g-forces built up so rapidly that my words came out garbled and unintelligible, as confirmed later by the cockpit voice recorder. I didn’t think the chances of surviving an ejection at Mach 3.18 and 78,800 ft. “I attempted to tell Jim what was happening and to stay with the airplane until we reached a lower speed and altitude. I instantly knew we were in for a wild ride. I jammed the control stick as far left and forward as it would go. An immediate unstart occurred on the right engine, forcing the aircraft to roll further right and start to pitch up. “On the planned test profile, we entered a programmed 35-deg. Unstarts were not uncommon at that time in the SR-71’s development, but a properly functioning system would recapture the shock wave and restore normal operation. “Without proper scheduling, disturbances inside the inlet could result in the shock wave being expelled forward–a phenomenon known as an “inlet unstart.” That causes an instantaneous loss of engine thrust, explosive banging noises and violent yawing of the aircraft–like being in a train wreck. Normally, these actions were scheduled automatically as a function of Mach number, positioning the normal shock wave (where air flow becomes subsonic) inside the inlet to ensure optimum engine performance. This was accomplished by the inlet’s center-body spike translating aft, and by modulating the inlet’s forward bypass doors.
The SR-71’s inlet configuration was automatically adjusted during supersonic flight to decelerate air flow in the duct, slowing it to subsonic speed before reaching the engine’s face.
“Several minutes into cruise, the right engine inlet’s automatic control system malfunctioned, requiring a switch to manual control. After refueling from a KC-135 tanker, we turned eastbound, accelerated to a Mach 3.2-cruise speed and climbed to 78,000 ft., our initial cruise-climb altitude. and completed the mission’s first leg without incident. The latter involved flying with the center-of-gravity (CG) located further aft than normal, which reduced the Blackbird’s longitudinal stability. We also were investigating procedures designed to reduce trim drag and improve high-Mach cruise performance. Jim Zwayer, a Lockheed flight test reconnaissance and navigation systems specialist, and I were evaluating those systems on an SR-71 Blackbird test from Edwards AFB, Calif. “By far, the most memorable flight occurred on Jan. And yet, I don’t recall too many periods of boredom during my 30-year career with Lockheed, most of which was spent as a test pilot.
“Among professional aviators, there’s a well-worn saying: Flying is simply hours of boredom punctuated by moments of stark terror. Graham’s book SR-71 The Complete Illustrated History of THE BLACKBIRD The World’s Highest, Fastest Plane) is priceless in conveying the experience of departing a Blackbird at an altitude of fifteen miles and speed of Mach 3.2. The following story told by Weaver (available in Col.
25, 1966 Lockheed test pilots Bill Weaver and Jim Zwayer were flying SR-71 Blackbird #952 at Mach 3.2, at 78,800 feet when a serious engine unstart and the subsequent “instantaneous loss of engine thrust” occurred. The first Blackbird accident that occurred that required the Pilot and the RSO to eject happened before the SR-71 was turned over to the Air Force. The team rose to the nearly impossible challenge, and the aircraft took its first flight on Dec. At Lockheed Martin’s advanced development group, the Skunk Works, work had already begun on an innovative aircraft to improve intelligence-gathering, one that would fly faster than any aircraft before or since, at greater altitude, and with a minimal radar cross section. The following story told by Bill Weaver is priceless in conveying the experience of departing an SR-71 Blackbird at an altitude of fifteen miles and speed of Mach 3.2ĭuring the Cold War, there was a need for a new reconnaissance aircraft that could evade enemy radar, and the customer needed it fast.